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Driving Range Buddy

Driving Range Buddy. Group 6 Xi Luo and Xuan Tang ECE 445 Spring 2007. Introduction. Driving Range Buddy is a device that allows golfers to measure their swing speed Features include: Displays swing speed Estimates ball distance Easy to read LCD “ Sweet Spot ” detector. Overview.

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Driving Range Buddy

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  1. Driving Range Buddy Group 6 Xi Luo and Xuan Tang ECE 445 Spring 2007

  2. Introduction • Driving Range Buddy is a device that allows golfers to measure their swing speed • Features include: • Displays swing speed • Estimates ball distance • Easy to read LCD • “Sweet Spot” detector

  3. Overview • Block Diagram / Schematics • Hardware • Software • Project Challenges • Calibration • Recommendations • Ethics

  4. System Overview

  5. Schematics

  6. Hardware Overview • Accelerometer • Microcontroller • LCD • Sensor / Amplifier

  7. Accelerometer • Analog Devices • ADXL320 • Output acceleration in terms of voltage continuously in X and Y axis • ±5 g Accelerometer • 1 g = 174 mv

  8. Microcontroller • Microchip 16F877A • Sample data • A/D conversions • 8 MHz clock • Calculation

  9. LCD • Seiko M16320 • 16x2 Display • Small and light • Only 25g • Low power consumption, 6.5mW

  10. Sensor / Amplifier • Vishay Microelectronics • 120Ω Strain gauge • Variable resistance • ∆Ω~0.05Ω • LM347 • Quad amplifier IC • Gain ~330

  11. Software • PIC software • C is used • Numerical Approximation is used to calculate speed • Distance calculations based on speed output

  12. Speed Calculation • Accelerometer outputs acceleration • Velocity equals integration of acceleration • PIC can only handle addition and multiplication • Direct integration is not available • Solution? • Numerical approximation

  13. Numerical Approximation Options: • Simpsons Rule • Trapzoid Rule • Riemman Sum

  14. Simpsons Rule Error:

  15. Trapzoid Rule

  16. Riemann Sum

  17. Project Challenges Liquid Crystal Display (LCD) Strain Gauge Circuit Amplifier

  18. Liquid Crystal Display • Problem • Displayed only black boxes • Fried first LCD • Rated 25mA • Drew ~400mA • Solution • Tested with test board • Retraced pin connections

  19. Liquid Crystal Display Spec Sheet Updated Table

  20. Strain Gauge Circuit • Voltage Divider • 5V / 130Ω = 38.5mA • 5V x (10Ω / 130Ω) = 0.384V • 1 resistor needed • Wheatstone Bridge • 5V / 120Ω = 41.6mA • 2 resistors + 1 potentiometer

  21. Amplifier • Basic Non-inverting • Differential • Instrumental

  22. Accuracy Calibration • Data Sampling vs. Radar • Over 200 samples taken total • Linear Approximations

  23. First Linear Approximation

  24. Second Linear Approximation

  25. Linear Approximation for High Speed

  26. Speed Function • Piece-wise function • <= 60: y = 0.39x + 40.33 • > 60: y = 0.54x + 35.04 • µ = ± 9.15% • σ = 6.70%

  27. Distance • U.S. Golf Association

  28. Recommendations • Condense board / component size • More durable material • Strain gauge data saving • Battery / LCD relocation • Sample higher speeds • More accelerometers

  29. Ethics • Safety • Hot components • Sharp edges • Loose or unstable pieces • Disclaimer • For entertainment purposes • Accuracy ±15% • Outdoor / open space use only • Acknowledgements

  30. References • http://probablegolfinstruction.com/SwingSpeed/how-to-use-golf-radar.htm • http://en.wikipedia.org/wiki/Image:Wheatstonebridge.png • http://en.wikipedia.org/wiki/Operational_amplifier#Basic_operation • http://courses.ece.uiuc.edu/ece445/projects/fall2006/project18_final_paper.doc • http://www.phys.ualberta.ca/~gingrich/phys395/notes/node110.html • http://www.usga.org/news/2006/april/distance.html • http://www.analog.com/UploadedFiles/Data_Sheets/ADXL320.pdf

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